With the production and packaging of, in particular, confectionery, for example large or small chocolate bars, the problem often ensues that the production machine is continuously operated for technical production reasons, while the packaging machine or plant is shut down during intermediate periods. Such intermediate periods can be caused by breaks prescribed for the operations in the packaging plant or through a fault, for example, changing a roller, at one or several packaging machines in the packaging plant. During all of these intermediate periods, the individual products supplied by the production machine must be transferred to a store. The store is then able to be emptied after these intermediate periods in that the unpacked individual products are then fed to the packaging plant.
A store of the above-mentioned type is known from DE 41 35 241 C1. The store comprises an input station and an output station which can be actuated independently of each other. Between the input station and the output station there is a storage line with a variable receiving capacity. Carrier plates for receiving the individual products as well as a conveying facility for transporting the carrier plates in a roughly circular motion through the store are also provided. The conveying facility consists of a plurality of single elements and separate drives. Thus, in the area of the input station an input elevator is provided and in the area of the output station an output elevator is provided for building up and working through full product stacks. The storage line between the input elevator and the output elevator is adapted for the common conveying of the stacks under congestion collecting in front of the output station of the output elevator. A separate input conveyor having its own drive is provided to transfer the carrier plates with the products lying thereon from the input elevator to the storage line. The same goes for the transfer between the storage line and the output elevator. An output conveyor with a separate drive is thus necessary. The number of the individual elements of the conveying facility and the number of the single drives is large in this type of known store. The operation of the input conveyor and the output conveyor may limit the performance of the store depending on the construction of these elements, whereby it may be necessary, for example, to stop the input elevator during the operation of the input conveyor. If the conveying paths of the input elevator and the input conveyor, cross each other this disadvantage is not only concerned with the forward stroke of the input conveyor but also with the backward stroke of the input conveyor. In this known store the carrier plates are freely movable in the store, making it possible to stack the empty carrier plates directly one above the other so that there is only the need of a small storage space. It is advantageous that more than 50% of the volume of the store may be used for the storage of carrier plates filled with individual products. Full stacks containing different numbers of carrier plates may be created from the carrier plates to have the possibility to quickly start product output from the store after starting the input. This known store however, still needs a plurality of single drive elements and drives.
A further store is known from U.S. Pat. No. 4,168,776. The essential component in this store is an endless chain which is wound around chain wheels. One portion of the chain wheels is fixed locally, while others of the chain wheels, assembled in pairs, are arranged so that they can move vertically. An input station and an output station, separate from the input station, are built onto the store and can be operated independently of each other, i.e. the store can be filled or emptied according to requirements. Therefore, the store can either be filled or emptied. In addition, it is possible to empty the store while also filling it, whereby completely different speeds can also be used. The known store has a relatively large dead area, i.e. roughly 50% of its volume serves only to merely convey the individual products through the store. Before the first individual item can be picked up again from the output station, the store must be filled to approximately half of its volume. Only the remaining half of its volume forms the storage line with a variable receiving capacity. If one of the essential properties of a store is to be able to allow removal of product at any time or to make this possible in a relatively short time, then the ratio of storage lines with a variable receiving capacity to the ratio of the dead space serving only for conveying product is relatively unfavorable. This means that such a store needs to be built relatively long and high if its storage line with a variable receiving capacity is to be, or needs to be, sufficiently large. The endless chain has carrier plates for receiving the individual products and a conveying facility for transporting the carrier plates on the chain in a roughly circular motion through the store is provided, whereby the individual drive wheels form a part of the conveying facility. Owing to the arc-like change of direction of the endless chain at the chain wheels, and the step-wise or jogwise transfer of the chain at the various positions, forces ensue at the change of direction positions which act on the individual products in a direction parallel to the main lengthwise plane of the carrier plates. In order to prevent the individual products from slipping off of the carrier plates and dropping down, the carrier plates must either have an appropriate shape or other measures must be applied.
It is clear that the peripheral speeds at the chain wheels are limited. The performance of such a store is thereby limited. In addition, such stores have the speciality in that the individual products can be removed again in the same sequence as they were fed therein i.e. the first individual item fed into the store is the first one to be taken out again.
For applications involving the storing of confectionery products, in particular large and small chocolate bars, it is known, based on the pricipal arrangement of the stores described above, to use gondolas which are connected via an articulated joint to an endless chain. These gondolas have a certain number of carrier plates above one another, for example, five carrier plates, whereby each carrier plate is designed and built to receive a row of confectionery items thereon. The pitch between the carrier plates within a gondola is, therefore, smaller than the distance of the lowest carrier plate of a first gondola from the uppermost carrier plate of a following gondola. The larger difference at this point is designated as a gondola gap or a gondola jump. On the other hand, however, this enables the gondolas to be able to negotiate the change of direction at the chain wheels, whereby the carrier plates always remain in a horizontally-aligned position. As the naked, unpacked items of confectionery are slid onto flat carrier plates, it is not possible to vary the shape of the carrier plates. The articulated suspension of the gondolas allows, on the one hand, the change of direction around the chain plates, and on the other the negative influence of the accelerating forces upon further movement of the endless chain is reduced. The disadvantage with such gondolas is that the steps in which the endless chain moves to the next stage, for example, in the area of the input station, must be of different a largeness. The larger path corresponds to the gondola gap and this gondola gap thereby determines the performance of the store because this movement represents the greatest load (stress) on the confectioneries. No confectionery product may fall from the carrier plate at the gondola. To bridge over the pitch between the carrier plates of a gondola, a similary large timespan as with overcoming the gondola gap is ready, so that a comparatively low speed is used.
The other disadvantage of such stores equipped with gondolas is that owing to the way the change of direction occurs, the store needs to be built to be very large although its storage line with a variable receiving capacity is relatively small. The sliding of the confectionery items onto the carrier plates in the area of the input station, and the sliding off from the carrier plates in the area of the output station puts corresponding loads on the items of confectionery because sliding friction has to be overcome. Incidentally, the push-on process must be so performed that the item of confectionery lies symmetrically about the hinge point of the gondola, or rather a vertical plane which passes through this hinge point. This means that with alternating confectionery formats, different paths have to be traced during the push-on process and/or carrier the plates, and gondolas matched to the format and shape of the format and shape of respective case in question need to be used on such stores.
A further disadvantage is that all gondolas in the store must be moved during certain operation conditions. For example, this is the case when a completely empty store with respect to its dead space, i.e. with respect to its storage line with a constant receiving capacity, is to be filled.
Furthermore, it is a disadvantage that with the known stores, the carrier plates fixed to the gondolas are difficult to clean, and is practically impossible to do during normal, continuous production. only if the store and the associated plant is shut down it is possible to carry out the tedious cleaning needed.